Gentoo is not exactly on my good list. I just don't like it. Something about compiling everything for a speed increase you won't notice because it'll be compiling KDE and OpenOffice in the BG lol.

Slackware is close enough to the point that if you order something off FreeBSD mall and Slackware store it'll come in the same box. And of course the Slackware books have the BSD logo on them on the back.